Actor Stephen Amell took to facebook to quell rumors that he was leaving Arrow and/or that the show was ending. Arrow first hit airwaves in 2012 and is current in its fourth season. The predominant fan theory is that the show will end after the fifth season as Oliver Queen was stranded on the Lian Yu for five years and the show would no longer have one of its staples, the flashback scenes. However, the specifics of Amell's contract would imply that there's potential for at least 7 seasons of Arrow as Amell's contract with The CW runs until 2019.
While his contract runs until 2019, Amell is quick to mention that doesn't necessarily guarantee that Arrow will continue for another three seasons. The Arrow showrunners have gone on to develop The Flash and CBS' Supergirl, along with numerous other side projects such as writing novels and comic books. Executive producers Marc Guggenheim and Andrew Kreisberg have already brought in new showrunners to share the load but if the show falls in the ratings or they decide the show has creatively run its course it's hard to imagine Arrow continuing until 2019.